Electric elevator system



27, 1929. R. A. WAITE ET AL r 1,725,772

ELECTRIC ELEVATOR SYSTEM Filed June 18, 1924 'Z'SheetS-Sheet 1 'R MQA/VM amvcuiou W, LMM

Patented Aug. 27, 1929.

UNITED STATES 1,725,772 PATENT OFFICE.

RAYMOND A. WAITE AND GEORGE W. LAUTRUP, OF YONKERS, NEW YORK, AS-SIGNORS TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A COR-PORATION OF NEW JERSEY.

ELECTRIC ELEVATOR SYSTEM.

Application filed .Tune 18,

another, stopping, reversing, and leveling at the various landings.

The system according to the present invention includes a hoisting motor,a motor generator set adapted to supply power to said hoisting motor ata variable voltage for operating it in either direction at variousspeeds, a brake adapted to have a slow, medium and quick operation inits application, a governor operative for regulating fields of thehoisting motor and generator in the event of the motor operating above apredetermined s cod, and various devices used in connection with theoperation of the hoisting mechanism to insure that the elevator car isbrou ht level with the landin s accurately and smoothly.

The control system is provided with a car switch in the elevator car foroperating the car at normal speeds in either direction and for stoppingthe car. Leveling switches car ried by the elevator car and adapted tobe actuated by cams in the elevator hatchway operate the elevator carfor bringing the car level with the landings. The brake haselectromagnetic releasing means having con nections with the controlsystem for-a quick application of the brake when the elevator car hasbeen brought to the landing by the leveling switches, for a. mediumapplication thereof during a reversal of the car by the car switch, anda slow application of the brake during the'stopping of the elevator caroutside of the leveling zones. The control system also provides a meansfor momentarily increasing the current in the generator field windingwhen the elevator car is being leveled whereby the car is broughtquickly and positively to the landing level. The generator has a seriesfield winding and means are provided for varying the ampere turns of theseries field for a given current through the armature,-as-for example byvarying the resistance of a shunt. around the series field so that theeffect of the series field is different during operation by the carswitch from that during operation on the leveling switch. The brake isprovided with a switch for rendering the control system inoperative toaccelerate the car above 1924. Serial No. 720,763.

a certain speed until after the brake has been released. The levelingswitches in cooperation with cams in the hatchway at the variouslandings are arranged to operate the control system. and are renderedoperative for such purposeduring the retardation of the car before ithas come to rest, so that the elevator car is brought smoothly to thelanding level. Means are provided in the control system whereby it ispossible to bring the car under the control of the car switch at anytime during the operation of the car by the leveling switches, andoperate it in either direction by the car switch. Certain switches areprovided with parallel resistances, or inductances or both in thecircuits of their coils for retarding their operation so as to obtain asmooth operation of the elevator car in accelerating, retarding,stopping and reversing.

This invention will be described in connection with the accompanyingdrawings, wherein one embodiment of the invention is illustrated and inwhich Figure 1 is a diagrammatic view of an elevator system; and

Figure 2 is a simplified (straight) wiring diagram, of the systemillustrated in Figure 1, wherein the coils and contacts of the vari ousswitches are shown as separate elements and wherein the lettersindicating the-various switches to which the respective coils and cntacts belong are prefixed to the reference urnerals.

The switch contacts shown sectioned represent the stationary contactelements of the various switches.

Referring to the drawings, the driving motor E with its shunt field EFreceives power from the line through knife switch I. This motor drivesgenerator GE, and these two units comprise a motor generator set. Thegenerator GE supplies power of a variable voltage to hoisting motor M.This variable voltage is obtained by control of the separately excitedgenerator field GF. The elevator car K and the counterweight CWT areoperatively connected to the driving motor M by cable 1. The operatingswitch A is located in the car K and serves to control the running ofthe elevator. A leveling switch L is located on top of the car and inconjunction with cams 2 and 3 located in the hatchway serves to controlthe leveling of the car with the floor landings. The control systemincludes reversing, accelerating and relay switches for controlling theoperation of the elevator bythe' operating switch A; also other relayswitches for controlling the leveling of the elevator car With thevarious landings. Power for the control circuits is supplied throughknife switch- J. The switches are'all shown in their deenergizedposition, the car being located level with the second floor landing.

Assume that it is desired to run the elevator from the position shown inan upward direction and then stop it at the third floor landing. Theoperator in the car moves the lever 4 of the operating switch A to theleft for an up motion of the elevator. The contact segment 5 of theoperating switch A bridges switch fingers 6, 7, 8, 9, 10 and 11 Whencontact segment 5 bridges fingers 6 and 7 a circuit is completed for theactuating coils of the up reversing switch B and the auxiliary fieldswitch H as follows-from the minus supply line, through knife swltch J,by wire 12, by wire 13, by wire 14, through back contact 15 of downreversing switch C, by wire 16, by wire 17, finger 6, segment 5, finger7, by Wire 18, through actuating C011 19 of up reversing switch B, byw1re 20, through actuating coil 21 of auxiliary field switch H, by wire22, by wire 23, by Wire 24, through knife switch J to the plus supplymain.

The energization of coil 21 of switch H causes this switch to operateand close its upper contacts and open its lower contact. The closing ofcontact 25 of swltch H closes the common .feed from theplus supply lineto the coils of the accelerating switches D, E, F, and G as will bedescribed below in connection with the circuits for these coils. Theclosing of contact 26 of switch H short circuits the economizingresistance SR, in series with the field MB of the hoisting motor M thecircuit being as follows-from the minus supply line, through switch J,by wire 12, by wire 13, by wire 27, through back contact 28. of switchG, by wire 29, by wire 30,

through contact 26 of switch H, by wire 31,

by Wire 32, through field MF and resistance PFR in parallel, by wire 33,through switch J to the plus supply line. The closing of this circultputs full field on the hoisting motor M. The closing of contact 34 ofswitch H makes circuit for the magnet of the brake BR as follows: fromthe minus supply line, through switch J, by wire 12, by wire 35, throughcontact 34 of switch H, by wire 36, through switch contact 37 on thebrake BR, by wire 38, by wire '39, through coil 40 of brake BR, by wire41,- by wire 24, through switch J to the plus supply line. This resultsin the release of the brake from the hoisting motor M and opening of theswitch contact 37 on brake BR.-

The opening of switch contact 37 on brake BR inserts in series withbrake coil 40 a resistance ABR, and the coil of an auxiliaryaccelerating switch 0 and its series resistance -OR in parallel withresistance ABR. The

of this arrangement is to utilize the time constant of the brake fortiming the accelcrating switches, and also for saving power bypreventing the acceleration of the car above low speed until the brakehas been released. The brake magnet is energized at the same time thatpoweris put on the motor, but the shoe does not lift at .once becausethe magnet itself has an inherent time constant and, also because theshoes (and lever arms, not shown in the diagrammatic representation)represent considerable mass which must be set in motion. When contact 37on the brake .opens, inserting resistance ABR in series with the magnetcoil 40, the current is cut down and hence, the'heating of the magnetcoil. The switch 0 in parallel -with resistance ABR will operate as thebrake shoe lifts, and close its contact 45 for the accelerating switchesE, F and G.

The opening of contact 46 of switch H opens the circuit of resistancePBR, which is in parallel with the coil of the brake.

There are two other resistances, PBR and PBR in parallel with the brakecoil, the circuit through these resistances being completedsimultaneously with the energization of the brake coil. The circuit ofthese parallel resistances when the lower contact 46 of switch H andcontacts. of switch Y are closedis as follows: from the coil 40 of brakeBR, by wire 39, by wire 38, through contact 37 of brake BR, by wire 36,by wire 47, by parallel circuits through resistancessistance PBR by wire52, by Wire 23, to

wi1'e24; the combined circuit from Wire 24 extends by Wire 41 to coil 40of brake BR. he purpose of these resistances is to control theapplication of. the brake under different conditions of operation aswill hereinafter be described.

The energization of the coil 19 of the up reversing switch B asdescribed above causes this switch to operate and close its uppercontacts and open its lower contacts. The switches-B and C areinterlocked by means of a walking beam 54 pivotally mounted for engagingcatches on the cores 55 and 56 of the switches B and C so'that when oneis operated the other is prevented from operating while the 'first oneis energized. The closing of the contacts 57 and 58 of switchB'completes the circuit for the field GF of generator GE as follows;from the minus 1 supply line'fth'ro'ugh switch J, by wire 12,

by wire 59, by wire 60, through contact 57 of switch B, by wire 61, bywire 62, through field GF, by wire 63, through coil 64 of relay N, bywire 65, througlrcoil 66 of relay Q,

by wire 67. bv wire 68, through contact 58 of switch B, by wire 69,through a part of resistance GFR to thep'oint 79, by wire 70,

through back contact 71 of relay R, by wire 72, b wire 24, throughswitch J to the plus supply line. Whilethe circuit for the coils ofrelays N and Q, is now complete, these relays do not operate as thecurrent is too low due to the resistance GFR in series with I down sideof thecar; switch to the accelerating switches respectively.

NVhen the segment 5' of the operating switch bridges fingers 6 and'S, acircuit is completed for the actuating coil 77 of-leveling switch relayT as follows; from the minus line to finger 6 as previously traced,segment 5, finger 8, .bywire 76, through actuating coil 77 of switch T,by wire 78, by wire 52, by wire 23, by wire 24, through switch J to theplus supply line. The switch T closes its contactg 'completing thecircuit for the leveling switch motor LM as follows; from the minussupply line, through switch J, by wire 12, by wire 80, through contact81 of switch T, by wire 82, through wire 83, by wire 24, through switchJ, to t 1e plus supply line. The cnergization of the leveling switchmotor results in the switch arm 86 with its roller 87 being moved awayfrom the. cam 2 and the switch arm 88 with its roller 89 being movedaway from cam 3, these two arms being connected to the motor LM by arm85 and connection 84. The leveling switch arms are then in such aposition that their rollers will not strike the cams 2 and 3 as the carmoves and the leveling switch contacts are kept open.

\Vith switches B, H, and T energized as just "outlined, the motor M willrun at a speed corresponding to the voltage supplied by the generatorGE. The voltage of this generator is increased in successive steps byshort eircuiting portions of the resistance GFR in series with the fieldGF. \Vhen segment 5 bridges fingers 6 and 9, a circuit is completed forcoil 94 of the first accelerating switch 1) as follows; from the minussupply line to' finger (i as previously traced, segment- 5, finger 9, bywire 90, through back contact91 of down reversing switch C, y e 92,through series resistance A11 by wire 93, through coil 94 ofaccelerating switch D, by wire 95, through contact 96 on switch E, bywire 97, through contact 98 on switch Q, by wire 99, through contact 25of switch H, by wire 22, by wire 23, by wire 24, through switch J to theplus supply line.

Switch 1) is thereby energized and closes its.

top contacts and opens its bottom contact.

The closing of contact 108 of switch D, completes the circuit for theholding coils of switches B, H and T as follows; from the minus supplyline, through switrh J, by wire 12, by wire 100, through holding coil101 of switch T, by wire 102, by wire 103, through contact 73 on switchB, by wire 104, through holding coil 105 of switch B, by wire 106, by

wire 107, through contact 108 of switch D,

by wire..109, by wire 110, through holding coil 111 of switch H, by wire22, by wire 23, by wire 24, through switch J to the plus supply line,This circuit for :the coils of switches B, H, and T is independent ofthe circuits originally completed for the actuating coils of theseswitches. The opening of back contact 112 of switch D' removes the short circuit around. coil 101 of switch '1, this contact bein of this coilby wires 113 and 114.

a The closing of contact 118 'of' switch D short circuits a portion ofresistance GFR as follows; frompoint 115 -in resistance GFR, by wire116, by wire 117, through contact 118' of switch D,-.by wire 119, topoint 205.

connected to the two ends ltesistance XFR has a short circuit as fol.-

accelerating switches when car switch A 5, finger 10, by wire 124,through resistance AR by wire 125, through contact of auxiliaryaccelerating switch 0, by wire 126, through contact 127 of switch D, bywire 128, by wire 129, through coil 130 of switch E, by wire 95, throughcontact 96 of switch a E, by wire 97, through contact 98 of switch Q, bywire 99, through contact 25 of switch H, by wire 22, by wire 23, by wire24, through switch J to the plus supply line. Resistances ARP and ARPare in parallel with the coils of switches D and E respectively; thecircuit for resistance ARP being from coil 94 of switch D, by-wire 95,contact 96 of switch E, by wire 97, contact 98 of switch Q,

by wire 99, through resistance ARP by wires 131 and 93 back to coil 94;and the circuit through ARP being, from-coil 130 of switch E, by Wire95, contact 96 of switch E, by wire 97, contact 98 of switch Q, by wire99, through resistance ARP by wires 128 and 129 back to coil 130. Theseresistances have .no function during the closing of switches Dand E butact when the switches are deenergized. Switch E is energized through thecircuit above traced and opens its bottom contact 96. The opening ofbottom contact 96 opens the short circuit extending from inductance 140,by wire 95, through contact 96 of switch E,-by wire 97, through contact98 of switch Q, by wires 99 and 141, back to inductance 140, so thatinductance 140 is inserted in. the circuit of coil 130 of switch E. Theinsertion of inductance 140 in the circuit of coil 130 of switch Edelays its action in closing its top contacts. The

closing of contact 134 of switch E short circuits another portion of theresistance GFR as follows; from point .132 in resistance GFR, by wire133, through contact 134 of switch E, by wire 117, through contact 118of switch D, by wire 119, .to point 205 of resistance GFR. By thus shortcircuiting another "portion of the resistance GFR, the

voltage supplied by the generator GE is further increased and thehoisting motor M runs at an increased speedfv The closing of' contact135 of switch E completes the circuit for coil 139 of the thirdaccelerating switch F as follows: from the minus supply line to finger10 aspreviously traced, by wire 124, through resistance AR, by wire 136through,

contact 135 of switch E, by wire 137, by

wire 138, through coil 139 of switch F, by

wire 95, through inductance 140, by wires 141 and 99, through contact 25of switch H, by w1res22, 23 and 24, through switch J to voltage suppliedby coil 139. Switch F will then operate, its

action being delayed by the inductance 140 in series with its coil. Theclosing of contact 144 of switch F short circuits another portion ofresistance GFR as follows; from point 142, by wire 143 through contact144 of switch F, by wire 133,through contact 134 of switch E and contact118 of switch D to point 205. By thus short circuiting another portionof the resistance GFR, the the generator GE is further increased and thespeed of the hoisting motor M is increased.

By the time switches E and F have closed, the current in the generatorfield GF has increased sufliciently to cause the switches Q, and M, thecoils of which are in closed establishes a holding circuit for the,coils of switches B, H and T, that is independent of switch D.

When segment 5 of operating switch A bridges fingers 6 and 11,.a circuitis completed for the coil 150 of the fourth accelerating switch G as'follows; from the minus supply line to finger 6 as previously traced,segment 5, finger 11, by wire 146, through resistance AR by wire 147,through contact 148 of switch F, by wire 149, through coil 150 of switchG, by wire 95, through inductance 140, by wire 141, by wire 99', throughcontact 25 of switch H, by wire 22, by wire 23, bywire 24, throughswitch J to the plus supply line. Switch G closes its upper contacts andopens its lower contact as a result of the completion of this circuit,its action being delayed by'the inductance 140 in series with its coil.The closing of, contact 153 of switch G short circuits another portionof the resistance GFR as follows; from the point 151 in resistance GFR,

GE is further increased and the speed of the hoisting motor M is againincreased The opening of lower contact 28 of switch G opens the shortcircuit by wires 27, 13 and 29 .around.- resistance SFR to insert it inseries with the field MF of'hoisting motor M, thereby weakening thisfield and causing the motor to run faster. Previous to the opening ofcontact-"2351M switch G, the coil 154 of switch Z wasshort circuited byenergized at this time to cause this switch to operate. The circuit forthe coil of switch Z is as follows; from the minus supply line throughswitch J, by' wire 12, by wire 13, through series resistance ZR,

' through coil 154 of switch Z, by wire 155,

by wire 32, through the field MF, by wire 33, to the plus supply line,and resistance SFR is connected across coil 154 of switch Z andresistance ZR, one end of resistance SFR being connected with resistanceZR and the other by wires 29 and 30, through contact 26 of switch H, bywires 31,- 32 and 155. Contact 158 of switch Z together with the contact160 of switch G short circuits the last portion of resistance GFR asfollows; from point 156 on resistance GFR, by wire 69, by wire 157,through contact 158 of switch Z, by wire 159, through contact 160 ofswitch G, by wire 152, through contact 153 of switch G, by wire 143,through contact 144 of switch F, contact 134 of switch E, and contact118 of switch D to point 205. By thus short circuiting all of theresistance GFR, the generator supplies full voltage to the hoistingmotor M and the latter runs at full speed, hoisting the elevator car atits full speed. I

It is to be noted that the opening of the short circuit aroundinductance 140, as described in connection with the operation of switchE, connects one end of this inductance to one end of each of the coilsof switches D, E and F, while the other end of inductance 140 isconnected through resistances ARP, ARP and ARP with the other ends ofthe coils of switches. D, E and F respectively. The object of thisinductance ,is for timing the closing of switches E and F and inconjunction with parallel resistances, the opening of switches D, E andF. It is to be further noted that inductance 140 is in the circuitof-the coil of switch G, the purpose being for timing its closing butithas no effect in timing its opening.

In the eventthat the elevator car shouldexceed the rated speed, afterthe resistance GFR has been entirely short circuited and the resistanceSFR inserted. in series with the motor field MF, a governor GOV oper--ates to short circuit the resistance SFR and at the same time tode'energize switch Z. Governor GOV is shown driven from" tire shaft ofmotor M, and is provided with a contact 161 which is normally open. Whenthe rated speed of the elevator car s exceeded, the governor closes thiscontact and coil 154 of switch Z and its series resistance ZR, andresistance SFR in parallel therewith are short circuited as follows:from resistance SFR, and resistance ZR, by wire 13, by wire 12, throughcontact 161 of the governor switch, by wire 162, by wire 32, by wire 155to the other side of coil 154 of switch Z, which is connected by wires32 and 31 through contact 26 of switch H, by wire 30, b wire 29, to theother side of resistance S R. The

resistance SFR is thus cut out of the circuit of the motor field MF, andthe deenergization of switch Z reinserts the last portion of resistanceGFR in the circuit of the generator field GF so that the speed of themotor is decreased by the combined effect of change of field strength ofboth the hoisting motor and generator.

Thus at full speed of the elevator the switches B, D, E, F, G, H, N, O,Q, T and Z are energized, the switches C, P, R, V, X and Y beingdeenergized, all of the latter switches except C, which is the downreversing switch, being used only during the leveling operation.

When the car approaches the thirdfloor landing, the operator centers thecar switch A, thereby disconnecting the fingers 7, 8, 9, 10 and 11 fromthe feed finger 6. The last accelerating switch, G, will openimmediately, there being no resistance in parallel With the coil of thisswitch to delay its opening. The opening of the upper contacts of thisswitch inserts part of the resistance GF R in series with the field GFof generator GE, thereby causing the voltage of the generator to belowered and the speed of the hoisting motor M to be correspondinglyreduced. The closing of the lower contact of switch G short circuits theresistance SFR and the coil 154 of switch Z, causing the latter to openits contact. The strength of field MF is thereby increased resulting ina reduction in speed of hoisting motor M. The accelerating switches D, Eand F then open, the opening of these switches being delayed by theelfect of the inductance 140 in series with their coils and theresistances ARP ARP and ARP in parallel with'the inductance and thecoils. By properly proportioning these resistances and the inductance,the desired delayed opening of these switches can be obtained. Theopening of these accelerating switches inserts the resistance GFR-insuccessive steps in series with the generator field GF, causing thevoltage of this enerator to be reduced and thereby gra ually reduce thespeed of the hoisting motor M.

As each step of the resistance GFR is inserted in series with the fieldGF, the strength of the latter is reduced. A sudden change is prevented,as each step-of resistance is inserted, by the action of the resistanceGPR in parallel with the field GF and coils of switches N and Q. Thecircuit vfor this resistance is as follows; from one end of field GF, bywire 62, through resistance GPR, by wire-68, by wire 67, through coil 66of switch Q, by wire 65, through coil 64 of switch N, by wire 63 to theother end of field GF. This arrangement also delays the opening ofswitches N and Q, the contact of switch Q remaining open to keepinductance 140 in the circuit with the accelerating switches for timingtheir operation in opening, and the contact of switch N maintaining thecircuit of the holding coils of switches B, H and T.

, When switch D opens, its back contact 112 closes and short circuitsthe holding coil 101 of switch T- This causes switch T to open anddisconnect the leveling switch motor LM from the line.- The arm 85 ofthe leveling switch L will move downward, tending to move the arms 86and 88 toward the cams 2 and 3 respectively. Assume that the operator inthe car centered the car switch when the car was at a distance fromthethird floor landing such that, at the time the leveling switch armsdrop back, the roller 87 on arm 86 strikes against the high surface 163of cam 2. This results in the closing of the upper contacts of theleveling switch, thereby completing the circuits for the levelingoperation.

The leveling switch has two movable arms 86 and 88, pivoted on an arm164. Arm 164 is connected with arm 85 and is pivotally mounted. Arms 86and 88 can move independently of arm 85, but an'upward-movement of arm85 results in the movement of arms 86 and 88 away from the cams 2 and 3respectively. Arms 86 and 88 of the leveling switch each have two setsof contacts, those on arm 86 controlling the up motion of the car andthose on 88 controlling the down motion, one contact of each set beingfor fast speed and one for slow speed- When the leveling switch motor LMis deenergized and the roller 87 on arm 86 bears against the surface 163of cam 2, the up set of contacts of the leveling switch is closed. Theclosing of contact 169 completes the circuit for the actuating coils ofthe'up reversing switch 13 and of the switch H as follows; from theminus supply line,through switch J by wire 12, by wire 165, through coil166 of switch P, by wire 167, by wire 168, through contact-169 ofleveling switch, by wire 18,

through coil 19 of switch 13, by wire 20,

through actuating coil 21 of switch H, by-

wires 22, 23 and 24, through switch J to the plus supply line. If thereversing switch B is still energized at this time as a result of switchN not having opened its contact 145,

which is in the circuit of the holding coil 105 of switch B, the closingof contact 169 of leveling switch L, will merely establish a circuit topermit coil 19 of switch B to maintain switch B closed. If however,switch B should have opened at this time, the energization of coil 19 ofthis switch by the closing of contact 169 of the leveling switch,results in the closing of switchB again and the re-establishment of thecircuits to the generator field GF. The closing of the other contact,171-, of the leveling switch establishes another short circuit aroundthe resistance XF R, this resistance being already short circuited bythe contact 122 of switch V as follows; from point 204, by wires 203, 24and 123, through contact 122 of switch V, by wires 121, 120 and 119, topoint 205. The short circuit established by the leveling switch is asfollows; from point 205, by wire 119, by wire 120, by wire 170, throughcontact 171 of leveling switch L, by wire 172, i

by wire 83, by wires 24 and 203 to point 204.

When contact 169 of the leveling switch closes, the coil 166 of switch Pis energized and this switch closes its contact, completing the circuitfor the coil of switch R as follows; from the minus supply line, throughswitch J, by wire 12, through coil 173 of switch R, by wire 174, throughcontact 175 of switch P, by wire 176, bywire 52, by wire 23, by wire 24,through switch J to the plus line. Switch R closes its three uppercontacts and. opens its lower contact.

The opening of lower contact-71 of switch R removes the short circuitfrom the portion of resistance GFR, between points 79 and 205, therebyinserting all'of resistance GFR in the field. The circuit through theresistance GF R is then as follows; from the minus line to point 79 ofresistance GFR as previously traced in connection with the operation ofswitch B, through all of resistance GF R, to point 205, by wire 119, bywires 120.

and 121, through contact 122 of switch V, by wires 123 and 24 to the lusline. 'As above stated, contact 171 o the leveling switch is in parallelwith contact 122 of switch V. The'elevator is then running at a speedslightly lower than the lowest speed obtainable by the car switch.

One of the upper contacts of switch R connects the up and down feedfingers 6 and 180, of the car switch A as follows; from finger 6,.bywire 17, by wire 16, through contact 177 of switch R, by wire 178, bywire 179, to finger 180. The object of this contact is to permit theoperator in the car to take the control. away from the leveling switchand to operate the car in either direction by the car switch at any timeduring the leveling operation as will hereinafter be set forth. Withoutthis connection, it would be possible supp for the operator to take thecontrol during the leveling operation only in the direction in which thecar is moving;

Upper contact 185 of switch'R completes the circuit for the coil ofswitch V as follows; from the minus supply line, through.

switch J, by wire 12, through coil 181 of switch V, by wire 1 82,through inductance 183, by wire 184, through contact 185 of switch it,by wire 186, by wire 52, by wire 23, by wire 24, through switch J to theplus y line. Switch V opens its contact 122, but the opening of thiscontact has no effect atthis time, as contact'171 of leveling switch isclosed and in a circuit parallel to contact 122 of switchV. Theoperation of switch V iii-opening itscontact 122 is retarded by theaction of the inductance 183 in series with its coil.

The third upper contact, 190; of switch R completes'the circuit for thecoil of switch X asfollows, from the minus supply line, through switchJ, by wire 12, through-coil 187 of switch X, through inductance 188, by

wire 189, through contact 190 of switch 1%,,

by wire 191, by wire 52, by wire 23, by wire 24, through switch J to theplus line. A resistance PR is placed in parallel with the coil of switchX and theinductance 188 to regulate the opening of this switch. When thecoil 187 of switch X is energized, this switch closes its contact, itsclosing being retarded by the action of the inductance 188 in serieswith its coil. I

The closing of the contact of switch X completes the circuit for coil196 of switch Y as follows; from the minus supply line, through switchJ, by wire 12, by wire 192, by wire 193, through contact 194 of switchX, by wire 195, through coil 196 of switch Y, by wire 197, by wire 52,by wire 23, by wire 24,'through switch J to the plus line. Switch Y'will operate and open its two contacts, 19 and 198. The openingofcontact 198 removes a short circuit around a part of resistance FS-whichis in parallelwith the series field GSF of the generator GE. .The seriesfield GSF is connected in the cir; cuit between thearmature of thegenerator GE and the armature of the hoisting motor M, and resistance FSis placed in shunt with this field. WVhen the switch Y is not energized,part of this resistance FS is short circuited by contact 198 of switchY, the circuit being by wires 199'and 200. The amount of this resistancethat is short circuited may bevaried to obtain the desired strength ofthe generator series field. This field is so wound that without anyresistance in parallel with it,'it would have too great an effect forthe proper operation of the car. The desired strength of this field isobtained by using alow resistance shunt. By increasing the amount ofthis shunting resistance when the switch Y operates, the strength of theseries field isincreased for the leveling operation. 49 of switch Yopens the parallel circuit around the brake magnet through resistancesPBR and PBRF.

lVhen the circuits are closed as just "traced the elevator car isrunning in the up direction on the high speed of the leveling operation.As the car gets nearer to the third floor landing, roller 87 on arm 86of leveling switch L runs off the surface 163 onto inclined sur face 201of the cam 2. This results in the opening of contact 171 of the levelingswitch, thereby opening the circuits for the high speed of the levelingoperation. The opening of this contact inserts resistance XFR in serieswith resistance GFR and the generator shunt field GF, causing this fieldto be weakened. A lower voltage is supplied by the generator GE to thehoisting motor M and the latter drives the car at a reduced speed, whichis the low speed of the leveling operation. A condenser C is placed inparallel with the contact 171 of the leveling switch to eliminate arcingwhen this contact opens.

As the car continues toward the landing, roller 87 remains in contactwith surface 201 of can12 and shortly before the car is level with thelanding the roller '87 rolls off of surface 261 onto surface 202 of cam2 thereby opening contact 169 of leveling switch L. The opening of thiscontact breaks the circuit to the coil 19 of reversing switch B, thecoil 166 of switch P and the coil 21 of switch H, thereby deenergizingthese switches which open and disconnect the generator field GF and thebrake magnet coil 10 from the line.

The holding coils 105 of switch B and 111 of switch H have already beendeenergized when contact 171 of leveling switch L opens,

so that these coils have no effect at that time.

The opening of the other contact The circuit to these coils was openedby 1 contact 108 on'switch D and the contact 1&5 on switch N, the latterswitch having opened as the current was reduced in the generator shuntfield GF.

-- Upon deenergizat-ion of coil166 of switch 1 P, its contact opens.This results in the opening of the circuit through the coil 173 ofswitch B, so that it opens its upper contacts and closes its bottomcontact. The opening of contact 190 of switch R deenergizes coil 187 ofswitch X which thereupon opens its contact 194, its opening, however.being delayed by the action of inductance 188 in series and resistancePR in parallel with the coil 187, The opening of contact 19-1 of switchXdeenergizes coil 196 of switch Y so that it closes its contacts 198 and49. The

opening of contact of switch R opens- .the circuit to coil 181 of switchV which thereupon closes its contact 122. The closing of contact 122 ofswitch V, and contact above.

71 of switch R short circuits resistance XFR and the portion ofresistance GFR between points 205 and 79. The gpening of contact 177 ofswitch R opens the connection between the up and down feed fingers, 6and 180, of car switch A. The closing of contact 198 of switch Y shortcircuits part of resistance FS in shunt with the generator series fieldGSF, thereby'decreasing the strength of this field. vContact 49 ofswitch Y establishes the parallel circuits around the brake magnet coilthrough the resistances PBR and PBR after giving a quick application ofthe brake for bringing the car to a stop at a floor when under thecontrol of the leveling switch, the resistance PBR alone beinginparallel with the coil of brake BR during the delayed closing of contact49. The switches are now in position for the next operation and theelevator car is level with the third fioor landing, theaccuracyof thestop being determined by the positioning of the cams with reference tothe landing and the controlling system described.

The above description of the operation of the elevator is for an upmotion of the car by both the car switch and the leveling switch. Asimilar operation is obtained for an operation of the car in the downdirection, the operator in the car moving the car switch in a directionopposite to that described above. When leveling inthe down direction,the other set of contacts are closed as a result of roller 89 on arm 88beingagainst cam 3.

The self leveling operation as described above may be summarized as,follows: On approaching the landing, the operator in the car brings thecar switch handle to the center position at such a time as to bring thecar to a low speed within the leveling zone, say for. instance, in thehigh speed zone below 'the landing. This action drops the auxiliaryleveling switch T, the contact of which interrupts the current :tor theleveling switch motor and allows the leveling. switch rollers to comeinto contact with the cam. As it is assumed that the car is in the highspeed zone, both high and low speed contacts for the up. direction inthe leveling switch close. Switch' P operates, completing circuit forswitch R, which makescircuits for switches V, X, and Y as described Whenthe low speed point on the cam isreached, the high speed contact on theleveling switc is opened, thereby inserting resistance XFR in serieswith the generator shunt field GF and-the resulting decreased voltage ofthe generator gives a very slow speed to the elevator car. On reachingthe end of the cam, the low speed leveling switch contact opens,dropping the reversing switch and applying the brake.

' Should the car overtravel the landing so that the down low speedleveling switch meagre l contact is made by the cam 3, current issupplied to the direction switch G and switch P. Switch P makes circuitfor switches R, V, X, and Y as before set forth. As the high speedcontacts on the leveling switch are open at the time, resistance XFRwould be in series with the generator field GF, resulting in a very weakgenerator field, if switch V operated .immediately to open its contact122. Therefore the operation of switch V is retarded so as to leave theresistance XFR short circuited for a short time in order to momentarilyprovide sufficient voltage for the motor armature to insure the startingof the car upon the leveling switch being closed when the car is in theslow speed zone. The

operation of switch Y in opening its contact 198 increases theresistance of the shunt FS across the generator series field, GSF,thereby causing a greater proportion of the armature current to passthrough the series field winding.

The action of the series field is to regulate the voltage on thehoisting motor armature so as to compensate for variations v of load 1nthe elevator car.

Switch Y is retarded in opening its con-- tacts by theretarded action ofswitch X in order to prevent the immediate change in the proportion ofarmature current flowing through the series field upon the closing ofthe leveling switch slow speed contacts.

Assuming that the elevator car is traveling in an u direction toavlanding, on the leveling switch, and it is desired to oper ate itdownwardly. The coil of switch B is energized and sincethe levelingswitch controls the operation of the direction switches B and C, and thebottom contact 74 on switch B has cut off the direct feed from the minussupply to the coil of the direction switch C, it would be necessary towait until the up leveling operation had been completed except ,for thefact that contact 177 of switch R which is closed during the levelingoperation completes a circuit supplying a feed from the minus supply toboth fingers 6 and 180 of the car switch A. Movement of the handle 4 ofthe car switch to the down direction first completes a circuit throughthe down direction switch C and switch H in a similar manner to that setforth for the direction switch B, but due to the fact that. directionswitch B is energized, the walking beam 54 between these switchesprevents switch C from operating. Further movement of handle 4 in thesame direction to cause the segment 5 to bridge three fin.- gers 180,206 and 207, on the down side closes the circuit of the coil of switch Twhich operates to energize the motor LM for raising the arm 85 ofleveling switch L. This resultsin the switch arms 86 and 88 with theirrollers being moved so as to be out of line of. the cams 2and 3 and thusopens the contacts of the leveling switch. The up direction switch B isthereby deenergized and when it opens, switch 0, which has already beenenergized, will close. Further movement of handle at will energize theswitches D, E, F, G, N, O, Q and Z so as to operate them in the mannerset forth in connection with the operation of the elevator car in the updirection. lVhile the elevator car is traveling downward at full speedthe remaining switches, 13, P, R, V, X and Y, are dcenergized. I

The control for the elevator affords a smooth operation from one speedto another and in stopping. While in the arrangement disclosed theoperation of the car leveling switch Lby motor LM and switch T iscontrolled from the third finger of the car switch A, it is founddesirable in some instances to interchange the order of these fingersand allow it to operate as fourth or fifth in order. In this case eitherone or two accelerating switches, D, or D and E, may be controlled fromthe car switchA without shifting the leveling switch L to inoperativeposition. As a result a continuous operation may he had in bringing theelevator cars of various rated speeds to a slop at the landings.

In order to obtain a smooth operation while stopping or reversing thecar, thebrake BB is controlled for quick, medium and slow application.The coil 40 of brake BR has a parallel resistance IBlt across it whichis never opened. This prevents an excessive voltage across the 601i whenthe circuit to it is broken, and the stop at the landing controlled bythis parallel resistance is a quick application of the brake to keep thecar from sliding past the landing. This operation takes place whenstopping by operation of the levelingcswitch, in which case the contact49 of switch Y is maintained open until the car has stopped, the actionof this switch, Y, being delayed by the retardation of switch X. Forstops be tween landings, the application of the brake is determined byparallel resistance equivalent to resistances PER, Pill-t and PBR all inparallel for a slow brake application, which brings the oar to restgradually and without shock. In this case switch Y remains inoperativein the stopping operation and its contacts remain closed, and switch llopens, closing its contact 46 so that all three resistances are in thecircuit. When making a quick reversal "resistances PBR and PER are inparallel around the brake coil so as to give a medium application of thebrake, just slow enough so that the brake will not set when making thereversal. Here switch Y renniins inoperative and contact -16'of switchll does not close. It will be understood that resistances IISR, PBR andPBR are so chosen as to give a discharge path of the proper resistancefor the brake coil for each condition.

What is claimed is 1. In an electric elevator system, the combinationwith a hoisting motor and a variable voltage source of energy therefor,of means responsive to the speed of said motor for jointly controllingthe field regulation of said motor and energy input into the motor fromsaid source to decrease the speed of the motor in the event that themotor speed rises to a predetermined value and to increase the speed ofthe motor after it falls to a predetermined value.

2. In an electric elevator system, the combination with a hoistingmotor, of control means therefor comprising a resistance adapted to beinserted in series with the motor field winding, and a variable voltagesource of power supply for the motor, and means responsive to the speedof said motor for short circuiting said resistance and de creasing thevoltage of said power supply in the event that the motor speed rises toa predetermined value and to increase the speed of the motor after itfalls to a predetermined value.

3. In an electric elevator system, the combination with a hoistingmotor, of control means therefor comprising a resistance adapted to beinserted in series with the motor field when the motor has reached a certain speed, a variable voltage source of power supply for the motorhaving electromagnetically operated switches adapted to control thevoltage supplied, means in the controlsystem for the hoisting motor foroperating said switches for increasing the voltage to the maximum andfor insertin said resistance in series with the motor lielo, and meansoperable to short circuit said resistance and operate one of saidswitches to lower the voltage of the power supply in the event of overspeed of the motor.

4:. In combination, an 7 electric motor, avariable voltage generator forsupplying energy to said motor, said generator having a iield winding,means for impressing voltage of certain values on said winding to causethe motor to run at normal speeds, and means for impressing voltage of alower value on said winding to cause the motor to run at a lower speedthan normal speeds, said last named means comprising means for initiallyand momentarily impressing voltage of a higher value than said lowervalue on said winding.

5. In combination, an electric motor, a variable voltage generator forsupplying current to said motor, said generator having a field winding,:1 source of current for said winding, means for controlling thedirection of the flow of current from said source to said winding tocontrol the direction of rotation of said motor, means for causing theapplication of voltage of certain values fro'iif said source to saidwinding to cause the motor to run at normal speeds in each direction ofrotation, and means for causing the application of voltage of a lowervalue'than said certain value from said source to said winding to causethe motor torun at a lower speed than normal speeds in each direction ofrotation, said last named means comprising means for initially andmomentarily causing the application of voltage of a higher value thansaid lower value from said source to said winding.

6. An electric elevator system comprising in combination, an elevatorcar, a hoisting motor, a variable voltage generator for supplying energyto said motor, control means including a leveling switch operable bymovement of the car in conjunction witlr cams in the elevator hatchwayfor causing the application of voltageof two different values to thegenerator field winding to causethe motor to operate the car at a fastand slow leveling speed, and means for ating the motor at normalvariable speeds in either direction with the power supplied by saidgenerator, and control means for operating said motor at lower than thenormal speeds in either direction by energy supplied from said generatorat lowervoltages, said last named means comprising means for initiallyand momentarily causing the application of voltage of a certain value tosaid winding and thereafter causing. the application of voltage of alower value than said certain value to said winding.

8. In an elevator system, an elevator car, a hoisting motor therefor, avariable voltage generator for supplying current to said motor, saidenerator having a field winding, a source of current for said fieldwinding,

means including reversing switches for controlling the direction of theflow of current from said source to said winding to control.

the direction in which the motor operates the car, means includingaccelerating switches for causing the application of voltage of certainvalues from said source to said winding to vary, within certain limits,the

voltage *applied from said generator to said motor to cause the motor torun at normal variable speeds 1n each direction of rotation, and means,including a leveling switch carsaid ried by said car and cams in thehatchway to be below'said certain limits and thus cause the motor to runat a lower speed than normal variable speeds in each direction ofrotation to facilitate the leveling of the car at the landings, saidlast named means comprising means for initially and momentarily causingthe application of voltage of a higher value than said lower value fromsaid source to said winding.

9. In an electric elevator system, the combination of an elevator car, ahoisting mo tor, a generator having a separately excited field windingand a series field winding and adapted to supply power to thehoistingmotor at a variable voltage, means for controlling the supply ofpower to the motor, a

leveling switch actuated by movement of the elevator car for controllingsaid power supply to the motor, and means controlled by the levelingswitch for causing a chan e of the ampere turns of the series fieldgiven armature current during the operation of the motor by saidleveling switch.

10. In an electric elevator system, the combination of a motor, ahoisting drum and an electrically operated brake, a source of energy forsupplying power to the motor and for operating said brake, a controlsystem including means for operating the motor in either direction fromthe source of power, means fo'rreversingits direction and bringing it toa stop, means for releasing the brake, "and means for regulating thespeed with which the brake applies to obtain a slow application of thebrake for stopping the elevator car between landings, a mediumapplication thereof on the reversal of the operation of the hoistingmotor, and a quick application thereof when stopping at landing-levels.i

11. In an electric elevator system, the combination of a hoisting motor,a variable voltage generator for supplying power'to motor, a controlsystem including direction switches, a plurality of accelerating 7switches interlocked with said direction switches and with each otherfor controlling the voltage applied to the motor from the generator,means'for retarding the operation of'the accelerating switches in openinwhen bringing the motor to a stop, an means operated after the motor hasattained a predetermined speed operable to retard the opening thedlrection switches.

12. In anelectric elevator system, the combination xoffa hoisting motor,a variable voltage generator for supplying power to said motor, acontrol system including direction switches, a' {,plurality ofaccelerating switches interlocked with said direction opening of saidswitches, and a switch operated after the motor has attained apredetermined speed and having a retarded action in opening adapted todelay the opening of the direction switches when the motor speed isdecreasing.

13. In an electric elevator system, the combination of a hoisting motor,a variable voltage generator for supplying power to said motor, acontrol system includlng direction switches, a plurality of acceleratingswitches interlocked with said direction switches and witheach other forcontrolling the voltage applied to the motor from the generator, a carswitch on the elevator car for controlling said switches, a levelingswitch adapted to be actuated by cams in the elevator hatchway foroperating the elevator car, means controlled by said car switch fordisplacing said leveling switch to an inoperative position, and meansfor retarding t e operation of the said direction and inter lockedaccelerating switches in opening, and means for returnlng the levelingswitch to its operative position before the direction switches open.

14. In an electric elevator system, the combination of a hoisting motor,a variable voltage generator for supplying power to said motor,a'control system including direction switches, a plurality ofaccelerating switches interlocked with said direction switches and witheach other for controlling the voltage applied to the motor from thegenerator, a car switch on the elevator car or controlling saidswitches, a leveling switch adapted to be operated by cams in theelevator hatchway and adapted to energize said direction switches for 0rating the elevator car at low speeds and ringing it to, the landinglevel, and means for rendering the car switchoperative to take thecontrol of said direction switches for operating the elevator car ineither direction at any time during the operation of the car by saidlevelingswitch.

In testimony whereof, we have signed our names to this specification.

RAYMOND A. WAITE. GEORGE W. LAUTRUP.

